STRENGTHENS GRIP AND IMPROVES DEXTERITY: Hand exercise rings build strength in the fingers, hands, wrist and forearms. Varied activities, including crushing, pinching and extensions work to improve the dexterity of both the fingers and hands. Perfect for athletes, musicians and physical therapy patients. PROGRESSIVE RESISTANCE LEVELS: Progressive levels of resistance allows the difficulty of each workout to be gradually increased as your grip improves. The color coded set includes 40 lb rings which can also be used for effective interval training, alternating between the three resistance levels in a single workout. PERFECTLY SIZED FOR A COMFORTABLE FIT: Sized to comfortably fit adult hands with an outer diameter of 3.45 and an inner diameter of 1.75. Perfectly sized for grip strength training for both men and women. DURABLE NONSLIP SILICONE CONSTRUCTION: Hand grip strengtheners are constructed with a premium silicone material that is odorless and latex free. The nonslip rings are also tear and crack resistant for long-term use.